The use of flip-chip technologies for integration of integrated circuits on a printed circuit board, as well as other integrated circuits in special configuration modules, starting to be used in certain areas. Flip-chip technology has proven itself a reliable and cost effective alternative to other integrated circuit integration techniques, including the use of Multi-Chip Module (MCM) technology. However, though this relatively new integration technology has started to become used in certain areas, many potential advantages in terms of product diversity and functionality have yet to be explored. Therefore, it has been deemed desirable to apply flip-chip technology to areas not previously explored, such as micro-machining techniques to obtain improvements therein.
A micro-electromechanical system assembly is designed to integrate a laser into its structure. The laser may be a vertical cavity surface-emitting laser (VCSEL). The MEMS assembly includes a micro-electromechanical substrate having an upper surface and a lower surface, the upper surface defined as having a first area and a second area. A first substrate bonding pad is positioned on the upper surface at a location within the first area, and a second substrate bonding pad is positioned on the upper surface at a location within the second area. Deposited upon the first and second substrate bonding areas are respective first and second solder material. A laser to be integrated in the MEMS assembly has a first laser bonding pad located on a first side, and a second laser bonding pad located on a second side. The laser is placed between the first substrate bonding pad and second substrate bonding pad such that they align with the respective first and second laser bonding pads. Upon a reflow of the solder material, a precise alignment of the laser is obtained while the reflow process occurs, at the same time providing a mechanical and electrical connection between the bonding pads. In a further embodiment, the MEMS substrate is configured with a trench portion into which is placed the laser having the first and second laser bonding pads. Placement of the laser in the trench, is at least one of a 45xc2x0 and 54.74xc2x0 from the substrate surface. Reflowing of solder on the substrate results in the laser being finely positioned and held mechanically stable.
In yet a further embodiment, the trench previously described includes a spring mechanism which carries a substrate bonding pad. The spring mechanism causing the laser within the trench to be maintained in a preferred position during and after the solder reflow process. Still yet another embodiment employs bimetallic cantilevers for positioning the laser and electrical interconnect.